I hosted a quick poll within the office recently, asking the question “What do you associate with summer?” The responses were varied, ranging from Wimbledon to extended daylight hours to grass stains (cricket). However, one thing that was pretty universal across the team was that summer means barbeques and sunshine.

If you were to ask most people what makes a good barbeque, they will probably say good food (when it’s black it’s done!), great company, plenty of drinks, and a spell of excellent weather. If you were to ask me, I would in all probability answer:

Charcoal burning

Functional design

Solid construction

Stylish looks

The standard components we would expect to see on a basic barbeque would be cast iron, heavy-duty plated steel, stainless steel and chrome-plated or porcelain-coated aluminum.

From my personal cooking preference we must not forgot the all-important charcoal.

The manufacture of charcoal

Charcoal is created when wood is heated under conditions where there is insufficient air for complete combustion. During this process the water contained in the wood is first driven off before the wood begins to break down.

The definition of charcoal sounds very simple until you realise the diversity of manufacturing processes and the numerous types of wood that can be used to produce it. In total there are more than 90 different processes that can be adopted to manufacture charcoal. These can be broken down into three distinct types: internal heating, external heating, and heating with re-circulated gas.

Without going into too much detail about the actual processes, the following table provides us with an indication of the differences.

One thing I will add to the table of production processes is a comment on the yield efficiency. If you look behind the chemistry of carbonisation, the best theoretical yield would be around 37 percent, assuming the carbon content of the dry, raw material is around 75 percent. Therefore, these modern industrial processes that are achieving a yield rate of around 34 percent are doubtless as good as you are going to get.

In the external heating processes the fuel used would almost certainly be natural gas or heavy fuel oil. A more detailed breakdown of cost for a modern retort process is detailed below.